In the food packaging industry, it is a common practice to assemble a cluster of food products (e.g. meat or poultry) which have been individually packaged, and put the cluster into a larger plastic film bag or envelope, which is then evacuated, then reinflated and sealed. This maintains the fresh quality of the food products during storage and transportation.
The present invention is applicable to this type of master package, as well as to one containing individual unclustered items.
To accomplish evacuation of the gas from the plastic film envelope, a vacuum probe is inserted into the film envelope and the gas is sucked out. One problem encountered with this process, is that the tip of the probe where the vacuum orifices are disposed is pressed against the contents of the envelope and becomes blocked and ineffective. These orifices, which may be grooves extending only a short way from the probe tip, become clogged and ineffective by the collapsing plastic film envelope.
Additionally, in the conventional approach the vacuum is applied through the probe inserted into the contents of the envelope, requiring that the envelope have its opening on the top surface of a generally broad and shallow package. This creates an envelope geometry which consumes a relatively large amount of plastic film for the product size.
One variation on the conventional approach is to evacuate a side or end loaded envelope by using a vacuum probe which enters in a horizontal plane. This side-inserted probe encounters the same problem as one inserted from above. As the plastic film envelope collapses around the probe, the grooves or slots at the tip of the probe tend to become blocked by the content of the envelope.
Accordingly, it is an object of the present invention to provide an improved method of evacuating gas from a gas tight envelope containing solid material disposed in one or more trays without clogging or blocking the vacuum probe which is evacuating the gas.
It is a further object of the present invention to provide a a methodology, for evacuating gas from a gas tight envelope, which avoids potential clogging or blocking of the vacuum probe by the collapsing envelope.